Iran’s Supreme Leader ayatollah Ali Khamenei has defended the presence of Iranian forces outside its borders, by calling it “the strategic depth of the Islamic regime”.

According to the IRNA, speaking at the army’s military academy, Khamenei reiterated that Iran’s “defensive power and capabilities are not subject to negotiations and haggling.”

Khamenei, who is also the commander in chief of Islamic republic’s armed forces claimed that the West opposes Iran’s increasing power “among nations” in the region and beyond, because it is “the strategic depth of the Islamic regime”.

He added that the answer to the opposition of the West was to rely on elements of national power.

The U.S. strongly objects to the presence of Iranian forces in Syria and Iraq and Iran’s support for the Lebanese Hezbollah.

On Sunday, Secretary of State Rex Tillerson who was visiting Saudi Arabia called on Iranian forces and militias to “go home” and allow Iraq to rebuild itself.

After President Donald Trump’s decision not to recertify the Iran nuclear deal two weeks ago, Iranian officials have adopted a harsher tone, rejecting U.S. demands and even threatening to expand their regional influence and missile capabilities.

The U.S. and its allies have repeatedly cautioned Iran that such a policy contradicts the spirit of the 2015 nuclear agreement and will not help to eliminate remaining economic sanctions or the effects of previous sanctions.